Single particle detection of micro/nano plastics based on recyclable SERS sensor with two-dimensional AuNPs thin films

Micro/nano plastics (MNPs) are widely recognized as a global environmental threat. Due to the lack of viable and reliable analytical methods, the identification and visualization of microplastics, especially nanoplastics, remains difficult to achieve, especially for single particle detection. Here, this study offered a simple, high-sensitive, and low-cost technique for MNPs identification using surface-enhanced Raman scattering (SERS) based on two-dimensional AuNPs thin films. This work realized the single particle detection of polystyrene (PS) and polymethyl methacrylate (PMMA), owing to the hot spot region created by the electromagnetic amplification of two-dimensional AuNPs thin films. The SERS-active substrate had a high SERS property in the single particle detection of MNPs as small as 200 nm. Moreover, this method can be used for the SERS mapping as a rapid detection technique for MNPs. In additon, this SERS-active substrate had good stability and reusable performance after 5 cycles. These findings indicated that this SERS strategy based on two-dimensional AuNPs thin films was an efficient and rapid method to identify nanoplastics in environment. And we believed that this kind of recyclable SERS sensor may create a universal strategy for the detection of MNPs at trace level.